Cylinder Head Bolt Torque

CYLINDER HEAD BOLT TORQUE/SEQUENCE





Tighten cylinder head bolts 1-12 in the sequence shown using a two step torque sequence:
(a) First to 47 Nm (35 ft. lbs.).
(b) Second to 122 Nm (90 ft. lbs.).
(c) After head bolts 1 - 12 have been tightened to specifications, tighten valley bolts A - H in sequence shown to 11 Nm (95 in. lbs.).

CYLINDER HEAD BOLT RE-USABILITY:





The Cylinder head bolts should be examined BEFORE reuse. If the threads are necked down, the bolts should be replaced. Necking can be checked by holding a scale or straight edge against the threads. If all the threads do not contact the scale the bolt should be replaced.

CYLINDER HEAD SURFACE VARIATION:

Inspect all surfaces with a straightedge if there is any reason to suspect leakage. The out-of-flatness specifications are 0.0007 mm/mm (0.0004 inch/inch), 0.127 mm/152 mm (0.005 inch/6 inches) any direction or 0.254 mm (0.010 inch) overall across head. If exceeded, either replace head or lightly machine the head surface.

The cylinder head surface finish should be 1.78-4.57 microns (15-80 microinches).